xref: /openbmc/linux/include/media/videobuf-core.h (revision 4a075bd4)
1 /*
2  * generic helper functions for handling video4linux capture buffers
3  *
4  * (c) 2007 Mauro Carvalho Chehab, <mchehab@kernel.org>
5  *
6  * Highly based on video-buf written originally by:
7  * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
8  * (c) 2006 Mauro Carvalho Chehab, <mchehab@kernel.org>
9  * (c) 2006 Ted Walther and John Sokol
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2
14  */
15 
16 #ifndef _VIDEOBUF_CORE_H
17 #define _VIDEOBUF_CORE_H
18 
19 #include <linux/poll.h>
20 #include <linux/videodev2.h>
21 
22 #define UNSET (-1U)
23 
24 
25 struct videobuf_buffer;
26 struct videobuf_queue;
27 
28 /* --------------------------------------------------------------------- */
29 
30 /*
31  * A small set of helper functions to manage video4linux buffers.
32  *
33  * struct videobuf_buffer holds the data structures used by the helper
34  * functions, additionally some commonly used fields for v4l buffers
35  * (width, height, lists, waitqueue) are in there.  That struct should
36  * be used as first element in the drivers buffer struct.
37  *
38  * about the mmap helpers (videobuf_mmap_*):
39  *
40  * The mmaper function allows to map any subset of contiguous buffers.
41  * This includes one mmap() call for all buffers (which the original
42  * video4linux API uses) as well as one mmap() for every single buffer
43  * (which v4l2 uses).
44  *
45  * If there is a valid mapping for a buffer, buffer->baddr/bsize holds
46  * userspace address + size which can be fed into the
47  * videobuf_dma_init_user function listed above.
48  *
49  */
50 
51 struct videobuf_mapping {
52 	unsigned int count;
53 	struct videobuf_queue *q;
54 };
55 
56 enum videobuf_state {
57 	VIDEOBUF_NEEDS_INIT = 0,
58 	VIDEOBUF_PREPARED   = 1,
59 	VIDEOBUF_QUEUED     = 2,
60 	VIDEOBUF_ACTIVE     = 3,
61 	VIDEOBUF_DONE       = 4,
62 	VIDEOBUF_ERROR      = 5,
63 	VIDEOBUF_IDLE       = 6,
64 };
65 
66 struct videobuf_buffer {
67 	unsigned int            i;
68 	u32                     magic;
69 
70 	/* info about the buffer */
71 	unsigned int            width;
72 	unsigned int            height;
73 	unsigned int            bytesperline; /* use only if != 0 */
74 	unsigned long           size;
75 	enum v4l2_field         field;
76 	enum videobuf_state     state;
77 	struct list_head        stream;  /* QBUF/DQBUF list */
78 
79 	/* touched by irq handler */
80 	struct list_head        queue;
81 	wait_queue_head_t       done;
82 	unsigned int            field_count;
83 	u64			ts;
84 
85 	/* Memory type */
86 	enum v4l2_memory        memory;
87 
88 	/* buffer size */
89 	size_t                  bsize;
90 
91 	/* buffer offset (mmap + overlay) */
92 	size_t                  boff;
93 
94 	/* buffer addr (userland ptr!) */
95 	unsigned long           baddr;
96 
97 	/* for mmap'ed buffers */
98 	struct videobuf_mapping *map;
99 
100 	/* Private pointer to allow specific methods to store their data */
101 	int			privsize;
102 	void                    *priv;
103 };
104 
105 struct videobuf_queue_ops {
106 	int (*buf_setup)(struct videobuf_queue *q,
107 			 unsigned int *count, unsigned int *size);
108 	int (*buf_prepare)(struct videobuf_queue *q,
109 			   struct videobuf_buffer *vb,
110 			   enum v4l2_field field);
111 	void (*buf_queue)(struct videobuf_queue *q,
112 			  struct videobuf_buffer *vb);
113 	void (*buf_release)(struct videobuf_queue *q,
114 			    struct videobuf_buffer *vb);
115 };
116 
117 #define MAGIC_QTYPE_OPS	0x12261003
118 
119 /* Helper operations - device type dependent */
120 struct videobuf_qtype_ops {
121 	u32                     magic;
122 
123 	struct videobuf_buffer *(*alloc_vb)(size_t size);
124 	void *(*vaddr)		(struct videobuf_buffer *buf);
125 	int (*iolock)		(struct videobuf_queue *q,
126 				 struct videobuf_buffer *vb,
127 				 struct v4l2_framebuffer *fbuf);
128 	int (*sync)		(struct videobuf_queue *q,
129 				 struct videobuf_buffer *buf);
130 	int (*mmap_mapper)	(struct videobuf_queue *q,
131 				 struct videobuf_buffer *buf,
132 				 struct vm_area_struct *vma);
133 };
134 
135 struct videobuf_queue {
136 	struct mutex               vb_lock;
137 	struct mutex               *ext_lock;
138 	spinlock_t                 *irqlock;
139 	struct device		   *dev;
140 
141 	wait_queue_head_t	   wait; /* wait if queue is empty */
142 
143 	enum v4l2_buf_type         type;
144 	unsigned int               msize;
145 	enum v4l2_field            field;
146 	enum v4l2_field            last;   /* for field=V4L2_FIELD_ALTERNATE */
147 	struct videobuf_buffer     *bufs[VIDEO_MAX_FRAME];
148 	const struct videobuf_queue_ops  *ops;
149 	struct videobuf_qtype_ops  *int_ops;
150 
151 	unsigned int               streaming:1;
152 	unsigned int               reading:1;
153 
154 	/* capture via mmap() + ioctl(QBUF/DQBUF) */
155 	struct list_head           stream;
156 
157 	/* capture via read() */
158 	unsigned int               read_off;
159 	struct videobuf_buffer     *read_buf;
160 
161 	/* driver private data */
162 	void                       *priv_data;
163 };
164 
165 static inline void videobuf_queue_lock(struct videobuf_queue *q)
166 {
167 	if (!q->ext_lock)
168 		mutex_lock(&q->vb_lock);
169 }
170 
171 static inline void videobuf_queue_unlock(struct videobuf_queue *q)
172 {
173 	if (!q->ext_lock)
174 		mutex_unlock(&q->vb_lock);
175 }
176 
177 int videobuf_waiton(struct videobuf_queue *q, struct videobuf_buffer *vb,
178 		int non_blocking, int intr);
179 int videobuf_iolock(struct videobuf_queue *q, struct videobuf_buffer *vb,
180 		struct v4l2_framebuffer *fbuf);
181 
182 struct videobuf_buffer *videobuf_alloc_vb(struct videobuf_queue *q);
183 
184 /* Used on videobuf-dvb */
185 void *videobuf_queue_to_vaddr(struct videobuf_queue *q,
186 			      struct videobuf_buffer *buf);
187 
188 void videobuf_queue_core_init(struct videobuf_queue *q,
189 			 const struct videobuf_queue_ops *ops,
190 			 struct device *dev,
191 			 spinlock_t *irqlock,
192 			 enum v4l2_buf_type type,
193 			 enum v4l2_field field,
194 			 unsigned int msize,
195 			 void *priv,
196 			 struct videobuf_qtype_ops *int_ops,
197 			 struct mutex *ext_lock);
198 int  videobuf_queue_is_busy(struct videobuf_queue *q);
199 void videobuf_queue_cancel(struct videobuf_queue *q);
200 
201 enum v4l2_field videobuf_next_field(struct videobuf_queue *q);
202 int videobuf_reqbufs(struct videobuf_queue *q,
203 		     struct v4l2_requestbuffers *req);
204 int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b);
205 int videobuf_qbuf(struct videobuf_queue *q,
206 		  struct v4l2_buffer *b);
207 int videobuf_dqbuf(struct videobuf_queue *q,
208 		   struct v4l2_buffer *b, int nonblocking);
209 int videobuf_streamon(struct videobuf_queue *q);
210 int videobuf_streamoff(struct videobuf_queue *q);
211 
212 void videobuf_stop(struct videobuf_queue *q);
213 
214 int videobuf_read_start(struct videobuf_queue *q);
215 void videobuf_read_stop(struct videobuf_queue *q);
216 ssize_t videobuf_read_stream(struct videobuf_queue *q,
217 			     char __user *data, size_t count, loff_t *ppos,
218 			     int vbihack, int nonblocking);
219 ssize_t videobuf_read_one(struct videobuf_queue *q,
220 			  char __user *data, size_t count, loff_t *ppos,
221 			  int nonblocking);
222 __poll_t videobuf_poll_stream(struct file *file,
223 				  struct videobuf_queue *q,
224 				  poll_table *wait);
225 
226 int videobuf_mmap_setup(struct videobuf_queue *q,
227 			unsigned int bcount, unsigned int bsize,
228 			enum v4l2_memory memory);
229 int __videobuf_mmap_setup(struct videobuf_queue *q,
230 			unsigned int bcount, unsigned int bsize,
231 			enum v4l2_memory memory);
232 int videobuf_mmap_free(struct videobuf_queue *q);
233 int videobuf_mmap_mapper(struct videobuf_queue *q,
234 			 struct vm_area_struct *vma);
235 
236 #endif
237